1. Field of the Invention
The subject invention generally relates to a method for determining a rate of rain falling on a surface. More specifically, the subject invention relates to a method for determining the rate of rain falling on a surface with an equation derived from a statistical point process equation.
2. Description of the Related Art
Various methods for determining the rain rate are known in the art. One example of such a method is disclosed in U.S. Pat. No. 5,119,002. Specifically, the '002 patent discloses a method that includes the steps of detecting a vibration caused by raindrops. The vibration is detected by a sensor which produces an output. The method continues by calculating an intermittent period based on both the sensor output and a constant value. The intermittent period is used to actuate a windshield wiper to remove the raindrops. The method of the '002 patent does not contain provisions to differentiate vibrations caused by raindrops and vibrations caused by non-rain disturbances. Consequentially, the method cannot accurately determine a rain rate and will result in improper actuation of the windshield wiper.
Another example is disclosed in U.S. Pat. No. 5,017,847. The '847 patent discloses a method of detecting the vibrations caused by rain, converting the vibrations into electrical signals, then using the electrical signals to directly actuate the windshield wiper.
Due to the deficiencies in the methods of the prior art, including those described above, there remains an opportunity to introduce a method that is capable of determining a rain rate based on the principles of a point process. The point process provides a means to determine a very accurate rain rate, since rain exhibits characteristics of a point process. Conversely, non-rain disturbances are inherently removed from determination of the rain rate, since non-rain disturbances do not exhibit the characteristics of a point process.